1. Field of the Invention
This invention relates to automatic vending machines having suitable means for selectively dispensing food products to a purchaser. More particularly, this invention relates to a vending machine having a plurality of vertically spaced shelves located in a housing wherein each of the shelves is slidably mounted in the housing for movement between a normal retracted dispensing position and an outwardly located product loading position.
2. Description of the Prior Art
Automated vending machines are well-known for dispensing food products upon insertion by a purchaser of a required amount of money. Such vending machines have various kinds of dispensing mechanisms depending on the particular types of food products which are being vended. One well-known class of vending machines is that known in the trade as helical coil vending machines or, alternatively, as spiral vendors. U.S. Pat. No. 4,061,245, issued to Joseph A. Lotspeich on Dec. 6, 1977, and assigned to the assignee of the present invention, is a typical example of a helical coil vending machine. Such machines are widely used for dispensing pre-packaged food products including rolled candy, mints and the like, and so-called "snack" products such as potato chips and pastries.
Most helical coil dispensing machines customarily include a housing which supports a plurality of vertically spaced shelves. Each of the shelves usually includes a plurality of elongated dispensing coils which run from front to back on the shelf. The rear end of each dispensing coil is operatively connected to an electric motor for selectively rotating the coil. Upon each consecutive rotation of the coil, the food product held in the foremost convolution is dispensed over the end of the shelf into a discharge space.
The shelves in many helical coil vending machines may be slid out of the machine housing when a door is opened to allow a service man to easily fill the coils with the food products to be dispensed. If the shelves could not be pulled out of the machine, the task of loading the machine would be difficult due to the lack of clearance space between adjacent shelves and the consequent difficulty in reaching the rearmost convolutions of the coil. Furthermore, there are times when each of the shelves are desirably completely removed from the housing rather than being only partially slid out for the purposes of reloading the shelf. Such complete removal may be needed if maintenance must be performed on any of the motor or control mechanisms located behind the shelf.
In "full size" helical coil vending machines of the type discussed above, a relatively complicated door and shelf interlock system is often used whenever the shelves are slidably mounted in the housing. Such an interlock system prevents inadvertent damage to the door and/or the shelves by preventing the shelves from being pulled out until the door is completely open and by preventing the door from being closed until each of the shelves has been replaced in the housing in its normal retracted orientation. One example of such a door and shelf interlock system is shown in U.S. Pat. No. 4,046,440 to Cox et al. Another example of another door and shelf interlock system is illustrated in U.S. patent application Ser. No. 888,138, entitled Vendor with Door and Shelf Interlock, filed on Mar. 20, 1978, and assigned to the assignee of this invention.
While such door and shelf interlock systems are eminently suited for the purpose for which they are designed, they are not economically practical in all situations. For example, current trends in the vending machine industry include the utilization of helical coil vending machines which are somewhat smaller than those of the prior art. In this new generation of vending machines, economy is a very important consideration. Thus, these "smaller" vending machines have fewer dispensing shelves than their "full-size" counterparts. They also do not have separate gum and mint dispensers as is used in the "full-size" machines. Although it is still desired that each of the shelves be slidable into and out of the machine for the purposes of shelf loading and removal, the likelihood of damaging the door and shelves of such a machine are not quite as great because of its smaller size. Thus, the conventional door and shelf interlock systems of the prior art are too expensive from a cost benefits standpoint to justify their use in the new and smaller vending machines. Nonetheless, there is still a need for locking the shelves inside the housing in a normal vending position, but yet allowing the shelves to be easily removed from the housing for the purposes of loading or removal.